This invention relates generally to low pressure poultry watering systems, and, more specifically, to valves and valve seals used in such systems for controlling the flow of water from a water feed line to a poultry watering cup.
Progressively, the commercial production of both eggs and chickens for broiling or cooking has advanced from the farmer with only a few hundred chickens to today's commercial producers who may have as many as one million or more birds in one location. As the size of commercial poultry operations has grown, so too has the significance of modern and reliable feeding and watering operations.
Most modern commercial poultry watering operations utilize a large number of chicken drinking cups which are constructed to automatically remain filled within a predetermined water level range. Today's largest poultry houses may have fifteen thousand such watering cups, and the poultry complex under the management and control of a single commercial producer may have ten houses on one site. Thus, there can be as many as one hundred fifty thousand such watering cups under one farm manager's domain.
It is apparent that due to the shear size of today's commercial poultry operations, it is imperative that watering systems be utilized which keep the drinking water in the cups, as opposed to the floor, and minimize leaks. It is well known that leaks through any such watering system can cause serious health problems to the poultry, both from resultant dampness and from the mixing of water with poultry manure to create ammonia and other dangerous and undesirable air contaminants. Indeed, the health problems to the poultry caused by the mixing of manure and water have prompted many large producers to install air quality sensors and large fans within the chicken houses in attempts to regulate the quality of the air within the houses. Leaking cups can, moreover, cause structural problems to the buildings, as well as pose environmental problems such as stream, lake and river pollution, and fly and odor problems.
Typically, poultry watering cups are connected to a low pressure water feed line, and the water flow through the feed line into the cup is regulated by a valving system utilizing a valve sealing cap. Whatever the valving system utilized for watering the poultry operation, it is critical that the valve sealing cap be capable of properly performing its sealing function at extremely low water feed line pressures. For example, to start baby chicks, the water feed line pressure may be set at three-quarter pounds or so. This value ranges upwardly to four pounds pressure on trigger cups. The valve sealing cap is also subjected to occasional pressure fluctuation such as sudden drops in pressure caused by peak demand for water, which occurs immediately after a feeding. Therefore, any seal design must be extremely sensitive with regard to the water pressure within the feed line. Further, the water valving system, and particularly the valve seal, must perform properly in the presence of contaminants in the water or hard particles such as chemicals in the water for medication or for other reasons, and must perform at both high and low temperatures to name but a few commonly encountered operating conditions.
A typical watering cup valve includes a hollow stem which engages an end of the water feed line, which stem forms a surface resembling a frustum of a cone having a valve inlet passageway situated therethrough. A rod or shaft extends through this passageway to support the valve seal in a position whereby the water pressure within the water feed line would normally urge the valve seal against the frustum portion of the stem to close the valve to fluid flow therethrough. Only when the valve seal is forced away from the stem frustum portion should water be allowed to pass through the valve inlet. When this opening force is removed, the water pressure within the water feed line is intended to cause the valve seal to once again engage the frustum portion of the stem and close the valve to flow.
Prior art valve seals, such as that illustrated in FIG. 6 of the accompanying drawings, usually have an internal taper which forms a feather sealing edge about the open end of the valve seal. This feather edge is designed to be slightly distorted by the water pressure within the water feed line and create a seal between the valve stem frustum portion and the internal face of the feather edge. It has been found that this feather edge valve seal is the essential shortcoming of the prior art poultry watering cup valve. The feather sealing edge of the prior art valve seal must maintain its integrity consistently and continuously under every conceivable operating condition, because even a minuscule break in contact along this feather edge will allow water to leak into the cup and eventually cause the cup to overflow and create the undesirable situations mentioned above. The criticality of the valve seal to the entire watering system is apparent when one considers that even a few drops leaking per cup over night, when the chickens are not drinking, can result in a literal flood of the chicken house.
It has been found that prior art feather edge valve seals can be quite easily distorted by their failure to resist chemical reaction with hard water or chemical additives to the water, and that they are subject to cold flow distortion when, for example, a spec of dust or other contaminant in the water becomes lodged under one edge in either a cold or hot condition. In sum, flaring out of the feather edge is considered by some to be inherent in the design of such valve seals, causing the same to inevitably flare and become incapable of forming a complete seal at low pressures with the valve stem, given enough time.
Previous attempts to solve some of the aforementioned problems with the feather edge valve seals have included the utilization of different materials, including thermoplastic materials such as vinyl, and other rubber-like materials. These materials have improved the valve seal's resistance to some of the conditions described above, but even the best have failed over a period of time due to the limitations of the feather edge design. Sometimes leaks don't show up when the water pressure within the feed line is at a normal poundage (for example two pounds), inasmuch as the water pressure is creating a sufficient force on the valve seal to hold it snuggly against the frustum portion of the valve stem. A drop of water pressure in borderline cases of seat distortion, however, will often allow water to leak past the valve seal through the valve inlet, resulting in undesirable water leakage.
Accordingly, there has been a need for an improved valve for controlling the flow of water from a water feed line to a poultry watering cup, which can satisfactorily prevent the flow of water from the feed line to the watering cup at virtually all normal operating pressures, and which is highly resistant to those factors which have caused prior valves to almost inevitably develop leaks. Such an improved valve should provide a reliable, non-fragile point contact seal which overcomes the drawbacks of the feather edge seal, and should be constructed of a material resistant to chemical or temperature degradation. Additionally, an improved valve seal is needed which, in connection with prior valves for controlling the flow of water from a water feed line to a poultry watering cup, can be substituted for prior valve seals to improve performance of the prior valves. Such improved valves and valve seals must be of simple construction, economical, and adaptable to various uses and requirements. The present invention fulfills these needs and provides other related advantages.